The present invention relates to an improved medical fluid cassette and a medical fluid control system including such cassette.
Medical fluid cassettes and fluid circuit elements adapted for use therewith interconnect medical surgical instruments (e.g. irrigating and aspirating handpieces) with control equipment so that the latter can control the flow of fluid to and from an instrument. When using typical medical cassettes and their fluid tubing in an operative environment, much care is taken for maintaining component sterility and for insuring their correct and reliable connections. In practice, a circulator and a scrub nurse assist in removing and setting up the fluid cassette and irrigation and aspiration tubing to the appropriate fixtures on the control equipment as well as the surgical instrument itself. There is, however, a desire to minimize handling of the tubing by the scrub nurse and circulator.
A number of known approaches exist for adapting medical cassettes to suitable control equipment. In commonly owned U.S. Pat. No. 4,713,051 there is disclosed a significant improvement in this field. Disclosed is an improved medical cassette in which much of the responsibility and reliability for the fluid connection is removed from human operators. This is because the specifics of the cassette construction and its geometry minimize the number of fluid transfer operations necessary for setting up the cassette to the control unit and instrument.
Cassettes like the foregoing present significant improvements over prior approaches in this area. While cassettes of this type are nonetheless successful, there is a continuing desire to improve their performance as well as to reduce the cost of their manufacture. In this regard, such a cassette generally cooperates with components in the control unit for selectively pumping and/or interrupting or occluding and/or otherwise controlling the flow of fluid through tubing segments. More specifically this cassette and others, such as described in U.S. Pat. Nos. 4,493,695; 4,627,833, 4,735,610 and 4,798,580 require the use of inherent rigid surfaces to cooperate with the tubing and console components, such as solenoid plungers and pumping assemblies, for effecting the desired fluid control. Such a cassette construction necessitates making it or significant portions thereof of rigid material. These construction factors add to the overall cost of the cassettes.